20. The anaplerotic reactions associated with the TCA cycle are a result of the:
(A) use of many of the TCA cycle intermediates in biosynthesis.
(B) decarboxylation reactions.
(C) irreversible nature of some of the TCA cycle reactions.
(D) oxidative nature of the TCA cycle.
(E) production of GTP and reduced coenzymes.

16. Urea and formamide are agents that denature double-stranded DNA (dsDNA) by (A) forming ionic bonds with the backbone phosphates. (B) breaking the phosphodiester bond. (C) changing the pH to cause hydrolysis. (D) competing effectively with the H-bonding between the base pairs. (E) intercalating between base pairs and disrupting van der Waals interactions.

17. In the Southern hybridization procedure, the gel after electrophoresis is treated with NaOH and then neutralized before blotting. What is the primary function of the alkaline treatment? (A) It neutralizes any acid soluble impurities in the gel. (B) It denatures the duplex DNA to single-stranded DNA (ssDNA). (C) It neutralizes any acidic phosphate groups that might prevent hybridization. (D) It inactivates any restriction endonucleases that may be in the gel. (E) It cleaves the DNA into smaller fragments to permit greater efficiency of transfer.

18. When transketolase acts on fructose 6-phosphate and glyceraldehyde 3-phosphate, the products are: (A) dihydroxyacetone phosphate and glucose 6-phosphate. (B) xylulose 5-phosphate and erythrose 4-phosphate. (C) 3-phosphoglycerate and two molecules of glyceraldehyde 3-phosphate. (D) xylulose 5-phosphate and ribose 5-phosphate. (E) 3-phosphoglycerate and glyceraldehyde 3-phosphate.

19. The _____ of pyruvate to acetyl-CoA is catalyzed by _____ (A) decarboxylation； pyruvate decarboxylase (B) carboxylation； pyruvate carboxylase (C) transacylation； pyruvate transacylase (D) dehydration； pyruvate dehydration complex (E) decarboxylation； pyruvate dehydrogenase complex

21. ATP made in glycolysis and the TCA cycle is the result of _____ phosphorylation, and NADH-dependent ATP synthesis is the result of _____ phosphorylation. (A) oxidative； electron (B) proton-gradient； oxidative (C) substrate-level； oxidative (D) substrate-level； electron (E) oxidative； substrate-level

22. The reaction, ATP + AMP → 2ADP, is catalyzed by: (A) adenylatephosphorylase. (B) AMP-phosphotransferase. (C) ADP mutase. (D) adenylate kinase. (E) None are true.

23. The brain prefers to use _____ as fuel, but under prolonged fasting or starvation it adapts to use _____.(A) fatty acids； glucose. (B) glucose； β-hydroxybutyrate. (C) glycogen； fatty acids. (D) glucose； fatty acids. (E) β-hydroxybutyrate； amino acids.

24. Given the following saturated fatty acid, how many β-oxidation cycles does it require to completely metabolize the above fatty acid to acetyl-CoA? (A) 2. (B) 3. (C) 4. (D) 5. (E) 6.

複選題25. Ketone bodies are produced by the β-oxidation of an excess of acetyl-CoA. Which of the followings are ketone bodies? ①②③④⑤(A) ①②③ (B) ①②④ (C) ②③④ (D) ②③⑤ (E) ②④⑤

26. Peptide A has amino acid sequence "CKGHNLRYEKDSAI". 　 1. Sophia used trypsin to digest the peptide. She obtained a pentapeptide. The pI of this pentapeptide is higher than 10. 　 2. Peptide A does not contain any residue with two chiral centers. 　 3. Peptide A contain only one aromatic residue. 　 4. Peptide A does not contain any residue which could be phosphorylated. 　 5. Peptide A does not contain any residue which could be modified with N-linked glycan in glycoproteins. (A) 3, 5 are correct. (B) 1, 3 are correct. (C) 1, 3, 4 are correct. (D) 1, 4 are incorrect. (E) 2, 3 are correct.